Until recently, hip-hop was too young for nepotism: its stars found more success disavowing elders than looking toward them. But A$AP Ferg, who performs at Webster Hall on Nov. 25, gained indirectly from his late father’s experience working as a graphic artist in Hamilton Heights, designing logos and merchandise for record labels. Ferg’s lineage colors the best of his sophomore album, “Always Strive and Prosper,” throughout which he conjures scenes of his father, uncle, and grandmother with a stylish eye and a bold tone.